In a computer network, a sender may transmit files, email messages, and other data to a recipient. The sender may encrypt the data to increase security in some circumstances. As an example, the sender may encrypt the data using a public key encryption technique. In public key encryption, two separate keys are associated with the recipient, a public key and a corresponding private key. The sender obtains the recipient's public key, encrypts the data using the public key, and transmits the encrypted data to the recipient. The recipient decrypts the encrypted data using its corresponding private key.